Lock bottom container

ABSTRACT

This invention relates to a paperboard container. The feature is the bottom formation which is formed from end flaps that hinge to the sidewalls. Three of the end flaps are interconnected and opposed end flaps are formed with a fold line so that the three interconnected end flaps can be hinged upwardly into an operative position in a flat folded condition. The single end flap is then interleaved with the folded portions of the three interconnected end flaps.

paperboard conwhich is formed FOREIGN PATENTS 157,954 8/1954Australia................. 1,017,965

ge to the sidewalls. Three of the end aps are interconnected and opposedend flaps are formed e interconnected end flaps can perative position ina flat folded ap is then interleaved with the terconnected end flaps.

829,563 8/1906 Anderson..............

12/1952 France 980,391 1/1965 Great Britain.....

Primary Examiner-Joseph R. Leclair Assistant Examiner-Steven E. LipmanAttorneyFetherstonhaugh & Co.

229/38 ABSTRACT: This invention relates to a tainer. The feature is thebottom formation 229/37 R 20m end flaps thathm with a fold line so thatthe thre be hinged upwardly into an 0 condition. The single end flfolded ortions of the three in 229/38 ReferencesClted UNITED STATESPATENTS 637,642 11/1899 United States Patent Inventor SydneyT.Butterfill Dorval, Quebec, Canada Appl. No. 842,954

Filed July 18, I969 Patented Nov.23, 1971 Assignee Conaolldated Paper(Bahamas) Llmlted Nuuau,Bahnmas 1 Claim, 7 Drawing Figs.

Int.

s41 LOCK BO'I'IOM CONTAINER PATENTEUNUV 23 I97! 3, 622 O65 SHEET 1 UF 2INVENTOR. SYDNEY T. BUTTERFI LL ATTORNEYS PATENTEnunv 23 l97l SHEET 2 BF2 FIG.6

INVENIOR. SYDNEY T. BUTTERFILL Bfazwzsflza ha ATTORNEYS exception tothis usual procedure consists of the LOCK BOTTOM CONTAINER FIELD OFINVENTION This invention relates to the manufacture of cardboardcontainers and is particularly concerned with a container having aself-locking bottom whereby the bottom end of the container may beclosed and locked without taping, stitching or glueing.

DESCRIPTION OF PRIOR ART The common type of cardboard container employsoverlapping flaps extending downwardly from the sidewalls of thecontainer for forming the bottom wall. Following inward folding of theflaps whereby they are overlapped, they are normally locked by beingtaped, stitched or stapled. Thus, the formation of a container bottomwall involves at least two steps, namely folding of the flaps and asubsequent locking step. One

prior application to the flaps of a press-seal adhesive so that alocking action takes place automatically as the flaps are folded.However, in this case there is the extra step of applying the presssealadhesive to the flaps at some time prior to the folding step.

SUMMARY It is therefore the main object of this invention to provide acontainerhaving a bottom wall flap arrangement which is selflocking asthe flaps are folded, thereby eliminating the usual further step oflocking the bottom wall by taping, stitching or stapling or eliminatingthe prior step of applying press-seal adhesive to the flaps.

It is a further object of the invention to provide a selflocking bottomin a carton construction which will not require any major modificationsto the equipment used for forming the container.

It is a still further object of the invention to provide a con-,

tainer having a self-locking bottom which can be set up quickly andeasily by hand at any packing station in a users plant and doesnot'require any additional material or equipment such as tape orstapling machines.

It is afinal and basic object of the invention to provide a cartonhaving a self-locking bottom which can be manufactured at a relativelylesser cost than self-locking cartons heretofore available and which canalso be set up at a lesser cost than required to set up similar cartonsknown heretofore.

PREFERRED EMBODIMENT the folding operation by which the bottom wall ofthe container is closed;

FIG. 3 is a view similar to FIG. 2 and showing a second step in thisfolding operation;

FIG. 4 is a view similar to FIGS. 2 and 3 and showing a third step inthe folding operation with'a portion of the carton being broken away forbetter illustration;

FIG. 5 is a perspective view similar to FIGS. 2 to 4 and showing thefinal folding step in closing the bottom wall of the container;

FIG. 6 is a top view of a carton having its bottom wall fully closed;and

FIG. 7 is a vertical cross-sectional view taken along the line 7-7 ofFIG. 6.

Referring to FIG. I, the container illustrated is formed of any one ofthe several container materials such as paperboard or corrugatedcardboard. The actual material used to fonn the container of theinvention is not critical as the self-locking bottom which is the chieffeature of this invention is adaptable to use in most containers of thisgeneral type which are either square or rectangular in cross-sectionalshape. The container is formed of a paperboard or cardboard blank andincludes four sidewalls 10 to 16 with two of the sidewalls beingconnected by the usual paper or cloth tape 18. The connection may alsobe made in another conventional manner, e.g. by gluing or stitching. Thecarton may or may not be provided with a number of upper end flaps foruse as a top closure.

The lower end of the container carries bottom wall forming flaps 10a to160 which consist of extensions of the sidewalls. The bottom walls ofcartons known heretofore have also normally been formed of sidewallextension flaps which are inwardly folded in an overlapping arrangementand taped or stapled.

In accordance with the present invention, the bottom wall flaps 10a to160 are so formed that when the flaps are inwardly folded and overlappedin a particular manner, a self-locking bottom wall is achieved as toavoid the need to subsequently tape, stitch or staple the flaps.

The above-mentioned self-locking feature is gained primarily through theprovision of a pair of scored fold lines 20 and 24 in two opposed endwall flaps which, in the illustrated embodiment, are the flaps 12a and160. A second principal feature is that the scored end wall flaps (12aand 16a) are joined at one side margin to one of the other flaps which,in the illustrated case, is flap 14a. Preferably, this joining can beintegral in the blank and this can be best achieved by locating the tape18 at the comer of sidewalls l0 and 12 or 10 and I6. However, apart fromeconomic reasons there is no other reason why the tape could not belocated at the corners fonned at the intersection of sidewalls l2 and 14or 16 and 14, provided the tape is extended as to also join the sideedges of flaps 12a and 140 or the flaps 14a and 16a.

The score lines 20 and 24 commence at their upper ends at points A and Band extend downwardly at an angle of 45". Thus, the length of the foldline varies with the length of the flaps 12a and 16a.

The first step in forming the bottom wall is to inwardly fold flap 1011,as shown in FIG. 2, until it rests against the inside surface of thesidewall 10. Then the other bottom wall flaps are folded as shown inFIG. 2 with care being taken to see that the flaps 12a and 16a foldinwardly along the score lines 20 and 24. When this last foldingoperation is completed, the carton appears as illustrated in FIG. 3.Then, as shown in FIG. 4, the flaps 12a and 16a, which are now foldedupon themselves, are raised upwardly against the inside surfaces of thesidewalls l2 and 16. Flap 10a is then folded down against the topsurface of flap 14a and finally, the flaps 12a and [6a are folded downalong the top surface of flap as shown in FIG. 5.

Following the folding operation above described, the bottom wall is noweffectively locked. It is found that the strength of the bottom wall soformed is even greater than if the wall is locked by taping or stapling.This is partly due to the fact that the weight of the contents of thecarton actually assists in the locking action.

It is even found that without the final folding step wherein the flaps12a and 16a are laid down upon the top surface of flap 10a, a quiteeffective locking action is achieved. In certain sizes and shapes ofcartons, it is found that it is preferable not to downwardly fold theflaps 12a and 16a as a final step as these flaps will overlap and createa bulge in the bottom of the carton. This is the case when the carton islonger in dimension C than in dimension D (see FIG. 3).

It will be appreciated that the self-locking action for the containerbottom wall of the invention is achieved through the connection of theside edges of the flaps 12a and 16a with the side edges of flap 14a ascombined with the feature of the fold lines 20 and 24 and by formingthese flaps of sufficient length that when they are inwardly folded theyeffectively form a means of blocking any tendency of the flap a to folddownwardly under the influence of the weight of the contents of thecontainer. It will be appreciated that there are variations possiblewithin the scope of the invention with respect to the dimensions of theend wall flaps as long as the aforementioned features are retained.

As previously mentioned, one of the chief advantages of the container ofthe invention is that the bottom wall does not require locking throughthe use of taping, stitching or stapling or press-seal adhesive strips.It will also be appreciated that the bottom wall can be readily andquickly formed by hand at the user's plant and in this connection, itwill be recognized that cartons of this type are normally shipped to theusers plant in a knocked-down fonn. Generally, the final manufacturingstep at the plant of the container maker is the application of the strip18 and pressing the carton into a flattened tube. Thus, the user simplyhas to open up the tube and form the bottom wall as described above.

What 1 claim as my invention is:

1. ln a container formed from a folded blank of paperboard or the like:

a. opposed sidewalls and front and rear walls foldably interconnected todefine a tube of rectangular cross section;

b. structures for closing the bottom of said tube comprising:

c. a closure flap foldably connected to said front wall and folded to apreliminary position in facing relationship with the inside of saidfront wall;

d. said closure flap being free from a fold line within the areathereof;

e. a second closure flap foldably connected to said rear wall;

f. an interconnecting flap foldably connected to each sidewall and to acorrelative side of said second closure flap;

g. a fold line in each interconnecting flap extending diagonally from afree edge of said interconnecting flap to the juncture of the lines offold between said interconnecting flap and the sidewall connectedthereto and between said interconnecting flap and the second closureflap connected thereto;

h. each of said interconnecting flaps being folded upon itself withelements thereof lying in facing relationship along the inner side of acorrelative sidewall;

i. said second closure flap being folded into position upon the foldingof said interconnecting flap along fold lines connecting saidinterconnecting flaps to said sidewalls;

j. said first closure flap being folded to a final position in facingand contacting relationship with said second closure flap;

k. each of said interconnecting flaps being folded while in theiraforesaid facing relationship along the fold line connecting it to arelated sidewall into a final position in facing and contactingrelationship with said first closure flap to maintain said first andsecond closure flaps in locked position.

8 8 i i t

1. In a container formed from a folded blank of paperboard or the like:a. opposed sidewalls and front and rear walls foldably interconnected todefine a tube of rectangular cross section; b. structures for closingthe bottom of said tube comprising: c. a closure flap foldably connectedto said front wall and folded to a preliminary position in facingrelationship with the inside of said front wall; d. said closure flapbeing free from a fold line within the area thereof; e. a second closureflap foldably connected to said rear wall; f. an interconnecting flapfoldably connected to each sidewall and to a correlative side of saidsecond closure flap; g. a fold line in each interconnecting flapextending diagonally from a free edge of said interconnecting flap tothe juncture of the lines of fold between said interconnecting flap andthe sidewall connected thereto and between said interconnecting flap andthe second closure flap connected thereto; h. each of saidinterconnecting flaps being folded upon itself with elements thereoflying in facing relationship along the inner side of a correlativesidewall; i. said second closure flap being folded into position uponthe folding of said interconnecting flap along fold lines connectingsaid interconnecting flaps to said sidewalls; j. said first closure flapbeing folded to a final position in facing and contacting relationshipwith said second closure flap; k. each of said interconnecting flapsbeing folded while in their aforesaid facing relationship along the foldline connecting it to a related sidewall into a final position in facingand contacting relationship with said first closure flap to maintainsaid first and second closure flaps in locked position.